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</pre><pre class="rust ">
<span class="doccomment">/// A macro for extracting the successful type of a `Poll<T, E>`.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This macro bakes propagation of both errors and `NotReady` signals by</span>
<span class="doccomment">/// returning early.</span>
<span class="attribute">#[<span class="ident">macro_export</span>]</span>
<span class="macro">macro_rules</span><span class="macro">!</span> <span class="ident">try_ready</span> {
(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">e</span>:<span class="ident">expr</span>) <span class="op">=></span> (<span class="kw">match</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">e</span> {
<span class="prelude-val">Ok</span>(<span class="macro-nonterminal">$</span><span class="kw">crate</span>::<span class="macro-nonterminal">Async</span>::<span class="ident">Ready</span>(<span class="ident">t</span>)) <span class="op">=></span> <span class="ident">t</span>,
<span class="prelude-val">Ok</span>(<span class="macro-nonterminal">$</span><span class="kw">crate</span>::<span class="macro-nonterminal">Async</span>::<span class="ident">NotReady</span>) <span class="op">=></span> <span class="kw">return</span> <span class="prelude-val">Ok</span>(<span class="macro-nonterminal">$</span><span class="kw">crate</span>::<span class="macro-nonterminal">Async</span>::<span class="ident">NotReady</span>),
<span class="prelude-val">Err</span>(<span class="ident">e</span>) <span class="op">=></span> <span class="kw">return</span> <span class="prelude-val">Err</span>(<span class="ident">From</span>::<span class="ident">from</span>(<span class="ident">e</span>)),
})
}
<span class="doccomment">/// Return type of the `Future::poll` method, indicates whether a future's value</span>
<span class="doccomment">/// is ready or not.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// * `Ok(Async::Ready(t))` means that a future has successfully resolved</span>
<span class="doccomment">/// * `Ok(Async::NotReady)` means that a future is not ready to complete yet</span>
<span class="doccomment">/// * `Err(e)` means that a future has completed with the given failure</span>
<span class="kw">pub</span> <span class="kw">type</span> <span class="ident">Poll</span><span class="op"><</span><span class="ident">T</span>, <span class="ident">E</span><span class="op">></span> <span class="op">=</span> <span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">Async</span><span class="op"><</span><span class="ident">T</span><span class="op">></span>, <span class="ident">E</span><span class="op">></span>;
<span class="doccomment">/// Return type of future, indicating whether a value is ready or not.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Copy</span>, <span class="ident">Clone</span>, <span class="ident">Debug</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">pub</span> <span class="kw">enum</span> <span class="ident">Async</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="doccomment">/// Represents that a value is immediately ready.</span>
<span class="ident">Ready</span>(<span class="ident">T</span>),
<span class="doccomment">/// Represents that a value is not ready yet, but may be so later.</span>
<span class="ident">NotReady</span>,
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> <span class="ident">Async</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="doccomment">/// Change the success type of this `Async` value with the closure provided</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">map</span><span class="op"><</span><span class="ident">F</span>, <span class="ident">U</span><span class="op">></span>(<span class="self">self</span>, <span class="ident">f</span>: <span class="ident">F</span>) <span class="op">-></span> <span class="ident">Async</span><span class="op"><</span><span class="ident">U</span><span class="op">></span>
<span class="kw">where</span> <span class="ident">F</span>: <span class="ident">FnOnce</span>(<span class="ident">T</span>) <span class="op">-></span> <span class="ident">U</span>
{
<span class="kw">match</span> <span class="self">self</span> {
<span class="ident">Async</span>::<span class="ident">Ready</span>(<span class="ident">t</span>) <span class="op">=></span> <span class="ident">Async</span>::<span class="ident">Ready</span>(<span class="ident">f</span>(<span class="ident">t</span>)),
<span class="ident">Async</span>::<span class="ident">NotReady</span> <span class="op">=></span> <span class="ident">Async</span>::<span class="ident">NotReady</span>,
}
}
<span class="doccomment">/// Returns whether this is `Async::Ready`</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">is_ready</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-></span> <span class="ident">bool</span> {
<span class="kw">match</span> <span class="kw-2">*</span><span class="self">self</span> {
<span class="ident">Async</span>::<span class="ident">Ready</span>(_) <span class="op">=></span> <span class="bool-val">true</span>,
<span class="ident">Async</span>::<span class="ident">NotReady</span> <span class="op">=></span> <span class="bool-val">false</span>,
}
}
<span class="doccomment">/// Returns whether this is `Async::NotReady`</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">is_not_ready</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-></span> <span class="ident">bool</span> {
<span class="op">!</span><span class="self">self</span>.<span class="ident">is_ready</span>()
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> <span class="ident">From</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> <span class="kw">for</span> <span class="ident">Async</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="kw">fn</span> <span class="ident">from</span>(<span class="ident">t</span>: <span class="ident">T</span>) <span class="op">-></span> <span class="ident">Async</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="ident">Async</span>::<span class="ident">Ready</span>(<span class="ident">t</span>)
}
}
<span class="doccomment">/// The result of an asynchronous attempt to send a value to a sink.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Copy</span>, <span class="ident">Clone</span>, <span class="ident">Debug</span>, <span class="ident">PartialEq</span>)]</span>
<span class="kw">pub</span> <span class="kw">enum</span> <span class="ident">AsyncSink</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="doccomment">/// The `start_send` attempt succeeded, so the sending process has</span>
<span class="doccomment">/// *started*; you must use `Sink::poll_complete` to drive the send</span>
<span class="doccomment">/// to completion.</span>
<span class="ident">Ready</span>,
<span class="doccomment">/// The `start_send` attempt failed due to the sink being full. The value</span>
<span class="doccomment">/// being sent is returned, and the current `Task` will be automatically</span>
<span class="doccomment">/// notified again once the sink has room.</span>
<span class="ident">NotReady</span>(<span class="ident">T</span>),
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> <span class="ident">AsyncSink</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="doccomment">/// Returns whether this is `AsyncSink::Ready`</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">is_ready</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-></span> <span class="ident">bool</span> {
<span class="kw">match</span> <span class="kw-2">*</span><span class="self">self</span> {
<span class="ident">AsyncSink</span>::<span class="ident">Ready</span> <span class="op">=></span> <span class="bool-val">true</span>,
<span class="ident">AsyncSink</span>::<span class="ident">NotReady</span>(_) <span class="op">=></span> <span class="bool-val">false</span>,
}
}
<span class="doccomment">/// Returns whether this is `AsyncSink::NotReady`</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">is_not_ready</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-></span> <span class="ident">bool</span> {
<span class="op">!</span><span class="self">self</span>.<span class="ident">is_ready</span>()
}
}
<span class="doccomment">/// Return type of the `Sink::start_send` method, indicating the outcome of a</span>
<span class="doccomment">/// send attempt. See `AsyncSink` for more details.</span>
<span class="kw">pub</span> <span class="kw">type</span> <span class="ident">StartSend</span><span class="op"><</span><span class="ident">T</span>, <span class="ident">E</span><span class="op">></span> <span class="op">=</span> <span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">AsyncSink</span><span class="op"><</span><span class="ident">T</span><span class="op">></span>, <span class="ident">E</span><span class="op">></span>;
</pre>
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